Television and high-frequency antenna systems



Feb. 12, 1952 M. P. MYIDDLEMAIVRK I I 2,585,6'7 0 TELEVISION ANDHIGH-FREQUENCY ANTENNA SYSTEMS Filed Oct. 19, 1951 2 SHEETSSHEET lATTORNEY Feb. 12, 1952 M. P. MIDDLEMARK TELEVISION AND HIGH-FREQUENCYANTENNA-SYSTEMS Filed Oct. 19. 1951 2 SHEETSSHEET 2 jaiae iii' Arrows?Patented Feb. 12, 1952 UNITED STATES PATENT OFFICE TELEVISION ANDHIGH-FREQUENCY ANTENNA SYSTEMS 8 Claims.

This invention relates to high frequency antennas as particularly usedwith television receivers or other high frequency systems employingselective directive radiation.

The present application is a continuation in part of my applicationSerial No. 241,959, filed August 15, 1951. In that prior application Idisclosed an antenna having a plurality of variously directed dipoleelements, combinations of which were selectable by a selector switch toachieve directivity of reception. The instant application has the samegeneral objectives as set forth in my prior application butspeecifically it discloses a system which is more versatile in that itactually provides for the selection of 16 directions.

Eight of these directions may broadly duplicate the other eight but thelobe patterns vary as willbe hereinafter set forth. The desireddirectivity is accomplished by the operation of a selector switch whichhas nine different positions in achieving the different directions asabove set forth. 360 of selected directivity are provided. In televisionpractice the switch will be manually operated but other systems mayemploy a motor drive.

The invention discloses broadly a pair of dipoles which are crossedperpendicularly or at other "angles so that four dipole rods areprovided as will be shown hereinafter. Any two of these dipole rods orpairs thereof may be selected in achieving a desired orientation of thean-- tenna and the remaining two will generally be shorted or connectedtogether, this feature having been found to be very desirable. Theselected combinations may comprise either straight or conical dipolesand may include reflector ele ments as will be hereinafter made clear.The entire arrangement is accomplished by a switch which is notable inregards to its simplicity of construction and use.

'The invention will be further understood in the following descriptionand drawings in which:

Figure 'l is a top view of an antenna system constructed according tothe instant invention, the switch elements being shown schematically;

Figure 2 is a front fragmentary view of a preferred form of antennaelements;'

Figure 3 is a cross-sectional view of the selector switch;

Figure 4 is a front view thereof; and' Figure 5 illustrates a modifiedembodiment oi the antenna arrangement.

[ Figure 5 illustrates a modified embodiment of the antenna arrangement.I I

Referring to Figure 1, the antenna elements are shown as being disposedin a horizontal plane as is customary although the disposition of theelements for the reception of vertically polarized waves will be evidentto those skilled in the art. The supporting member comprises a rod H)through which extends a U-shaped holder ll.

Holder II in cooperation with clamp l2 grips the vertical mast l3 aswill be evident. Such structure serves to support the antenna elementsand insulator brackets on a roof or other side.

To the ends of rod H] are connected a pair of insulator brackets l4 andI5. These are of electrically insulating material such as Bakelite orthe like. Insulator I4 is angular in form, having' two arms, each ofwhich support the antenna elements in a predetermined angularrelationship. Thus, each arm is formed with one or more grooves 16 intowhich the antenna elements, in this case dipole rods, fit. Theillustrated system employs crossed dipoles, each com-- prising twodipole rods which are designated in the drawing as I and 4, and 2 and 3.Referring to Figure l, the dipole rod 2 fits into a groove l3 wherein itis retained by a metal clamp I3 which is tightened by a bolt I9. Thisarrangement is more or less conventional and it serves to maintain thedipole rod 2 firmly in the groove.

It will be understood that whereas a complete antenna system, as will behereinafter described, includes only four dipole rods such as might bededuced from the view of Figure 1, ac- W tually each insulator bracketI4 may have three diverging grooves as illustrated in Figure 2, thesegrooves holding the dipole rods 2, 2a and 2b. In asmuch as the bracketl8 clamps all three of thesedipole rods simultaneously, it will beevident that they function as a unit so that the same principles ofoperation apply to either a two or three element dipole rod arrangementor a single one, as the case may be.

Dipole rod 3 is similarly disposed in the opposing insulator arm asillustrated in Figure 2, while the other dipole rods 3a and 32) may alsobe included in the arrangement.

The other end of the antenna employs the insulator l5 and the dipolerods I and 4 each of which may be one of the group of three as abovedescribed. Viewing the antenna from above as in Figure 1, the structuremay be described as comprising two crossed or perpendicularly relateddipoles, each consisting of two dipole rods and all the rods beingdisposed in stellate form relative to each other.

Wires 24, 25, 26 and 27 are respectively conl ficted to each of theinner terminal ends of the dipole rods 2, 3, l and 4. A suggested mannerof connection is to connect the wires to the bolts 19 of the clamps l8as illustrated in Figure 1, such connection being transmitted to thedipole rods themselves by the metal clamps. Wires 2% to 21 will be ofthe transmission line type. Thus, for example, wires 24 and 25 may bethe two conductors of twin transmission line having the usual 300 ohmimpedance. In the same way wires and 2'1 may be the conductors ofanother twin transmission line. Of course, other conventionaltransmission lines may be employed. It is also proposed that a tubularform of transmission line having the conductors spaced 90 apart may beemployed as may be a square transmission line, either solid or tubular,with the four conductors embedded longitudinally in each corner thereof.

In achieving the directivity accomplished by the apparatus of theinstant invention, a switch 38 is employed. Switch may be disposedwithin or adjacent to the television receiver cabinet probably dependingupon whether it constitutes original equipment or is subsequentlysecured.

It is also suggested that the switch may .be disposed adjacent to theantenna and actuated by iiexible cable instead of by the rigid shaftshown. As will be hereinafter described, switch 30 is manually operatedby the user of the television receiver in order to select the propereffective direction and thus secure the best reception.

Switch 39 is of the type referred to as a flat, wafer switch ofso--called staked construction. For example, switches of this type aremanufactured by Centre-lab of Milwaukee, Wisconsin or Qak Mfg. Co. ofChicago, Ill., and are standard in the art. As illustrated in Figures 3,the switch includes a housing 3! having ears 32 and 320. whichfacilitate its connection to a support which may be the televisionreceiver cabinet.

A shaft 33 operates the rotor contacts. A threaded bushing 3-4 surroundsthe shaft and a nut as thereon serves to secure the shaft in respect tothe housing 3 I. A frame 3'! is mounted on a bushing 33 which is in turnsecured to bushing 34. Bushings 34 and 38 are fixed relative to housing3! and do not rotate with shaft A toothed wheel 39 is secured to frame3! so as to be immovable therewith. A spring disk 48 having a tooth ,4!is employed to fix the position of the shaft :at definite points, thetooth 4i mating with any one of the teeth of wheel for this purpose.

Frame 31 includes a pair of arms which are riveted to the stationaryinsulator plate 42. Plate 42 carries a plurality of clips to whichconnections are made. In the instant embodiment, such clips are disposedon both faces of plate 32. It is to be understood that no claim is .madeto the construction of the switch as above described since suchconstruction is broadly known and conventional in the trade.

In the preferred embodiment disclosed herein, plate 42 carries a seriesof 7 clips or contacts on each face thereof, so that in all, '14 clipsare provided. In order that the clip arrangement may be more readilyunderstood, the respective faces of plate 12 are illustrated in Figure 1as being side by side and are respectively designated as X and Y. Itwill be understood however, that X and Y are the opposite faces of thesame plate 42.

Referring to face Y, 6 of the clips are numbered in the drawing tocorrespond to the antenna elements to which they are connected.

cally connected small rotors 65 and 59.

Thus, clip 3Y is connected by wire 3W to dipole rod 3. Clip 4Y isconnected by wire 4W to dipole rod 4. Clip 2Y is connected by wire 2W todipole rod 2. The remaining three clips are interconnected as by wire 45and are each labeled IY, they being connected by wires [W to dipole rodl. Clip 46 is the output element and is connected by wire 4'? to one ofthe input terminals of the television receiver.

Face X of plate 42 has the same arrangement of clips. Thus clip 4X isconnected by the wire soldered thereto, to dipole rod 4. Clip 2X islikewise connected to dipole rod 2 and clip 3X is connected to dipolerod 3. The remaining three clips are connected respectively to dipolerods 2, 3 and 4 and are designated as 2x, 3x and 4a: to distinguish themfrom the other three clips of face X. Clip 59 is the output terminal andis connected by wire 5| to the other input terminal of the televisionreceiver so that wires 41 and 5] represent the signal input to thereceiver.

Switch 30 includes a rotor insulating .plate which carries the rotorcontacts. Theopposite faces of the rotor plate 55 are designated as 56and 51 respectively. Face 51 supports a long, arcuate rotor 58 and ashort rotor -59. Rotor 55 has three contacts designated as 60, 6! and 62respectively. Rotor 55 has one contact designated as 63. 7

Face 55 of the rotor plate has similarly .arranged rotors 513 and 65,the three contacts of rotor 64 being designated as 66, 61 and 68respectively, and the contact of rotor 55 being designated as 69. Aswill be noted in Figure 3, the small rotors 59 and 65 are connected backto back, these rotors serving as the shorting elements as will behereinafter made clear.

When knob iii of the switch is rotated so as to rotate shaft 33,different switch positions are established because the rotor contactsmeet different combinations of clips. It will be noted that output clips5% and 5! are longer than the remaining clips so they effect electricalcontact with the respective rotors 58 and 64 regardless of the positionof the rotor contacts. Thus, the rotors'effectively establish aconnection with 'selected antenna elements which are in turn transmittedto the output clips 45 and 5t.

In the position of the switch rotor plates .illustrated in Figure 1, itwill be noted that rotor contact 68, meets clip 3X so that dipole rod 3is selected. Rotor contacts 66 and 61 are not used. Rotor contact '69meets clip 43:. On the opposite side of the plate, rotor contact 62meets clip 2*! so as to be effectively connected todipole rod 2. Rotorcontact 59 is in the same way connected to dipole rod I. The :result ofthis position, which we may call position I, is to apply dipole rods 3and '2 to the respective output wires 5! and 4?! respectively, while thedipole rods l and 4 are shorted by the electri- Examining thearrangement of the dipole rods in Figure 1, it will be evident at thistime that the direction indicated by arrow 11) is accomplished. Inotherwords, dipole rods 2 and 3 serve as forward elements of an inclinedV-type antenna while dipole rods 1 and 4 are connected together at theirterminal ends and jointly serve to :some extent as a reflector. As iswell understood, the direction achieved thereby is forward of the dipolerods 2 and 3 along a line substantially loisecting the angle between.such rods.

In order that all nine Switch positions may be graphically set forth,the following table will indicate every position of the X and Y contactsand the directivity achieved thereby:

Briefly summarizing the information in the foregoing table, it may benoted as follows:

When knob is switched to position 2, the clips 2X and 4Y are connectedthrough the rotor contacts 68 and 62 respectively to the dipole rods 2and 4. At the same time, the shorting contacts 63 and 69 are connectedto clips 3a: and IY so as to connect the dipole rods 3 and I. Thus, theoutput of dipole rods 2 and 4 is fed to the television receiver. It willbe observed that dipole rods 2 and 4 constitute a substantially straightdipole. As is well-known, the lobe pattern of such a dipole is broadsideto it. Accordingly, directivity is accomplished in the direction ofarrows H and 12, a straight dipole being bi-directional as iswell-known.

The other combinations shown on the above table will achieve thedirection illustrated by the arrows I3 to 85 pursuant to well-knownradiation principles. In position No. '7, it will be noted that dipolerods 3 and 4 are connected to the X output terminal while rods I and 2are connected to the Y dipole terminal. This is equivalent to fed,forward elements of a V-type antenna inclined in the direction of arrows18 and 19 respectively, and accomplishing directivity in suchdirections. It will be noted that arrows l8 and i9 actually duplicatebroadly the directions of arrows I4 and TB. However, in the directivityshown by arrow 10, the dipole rods 2 and 3 were used as the forwardelements while rods l and 4 served as reflector elements. On the otherhand, in regard to the directivity achieved by arrow 19, rod 3 isconnected to rod 4 and rod 2 is connected to rod I. It will berecognized that such a variation changes the lobe pattern to aconsiderable degree. In other words, while broadly speaking, arrows 19and 19 point in the same direction, actually the patterns of receptionvary. Therefore, a station which is somewhere in the sector defined byrods 2 and 3 may be better received in position 1 than in position I.The user may try either one of the arrows 10 or 19 to receive a stationin such sector.

Position 8 achieves directivity in the direction of arrows B9 and BIwhich duplicate those of arrows 17 and 13 in the same general manner setforth above. Finally, in position 9, the dipole rods of each dipole areinterconnected such as in a turnstile antenna and the pattern issubstantially in four directions along each dipole rod. This completesthe 16 directions, 8 of which are believed to generally duplicate theremaining 8 but with different lobe patterns. In the various directionsaround the 360 of a circle, the user is given the option of selectingdifferent reception patterns so that he can choose the one giving thebest results. The housing 3! of the switch may include indicia 90wherein the 9 switch positions are indicated. Of course, other indiciasuch as arrows or channel numbers may be employed.

It will be understood that the antenna elements may take variousconventional forms and may be stacked as is customary. For example, inFigure 6 is illustrated a system of dipole rods 9l--94 which are stackedin respect to rods -98. The upper dipoles are connected to the lowerdipoles by rods from the center of which extend the output wires 99 toI02 as is customary. It will be further understood that such antennasystems may assume other conventional forms such as folded dipoles asset forth in my prior application or rods having conventional Whiskersor stubs, these being well-known substitutes or variations of simpledipole elements. The dipoles may be crossed at 90 as illustrated or atanywhere from 60 to Whereas Figure 2 shows three dipole elementsfunctioning as connected dipole rods, either one or two or more may beused as will be understood. Furthermore, the dipoles may take the formof conical or fan-like sheets which are also conventional substitutesfor ordinary single dipoles.

It will be recognized that inasmuch as the antenna is used in a broadband system, the dipoles are necessarily cut to compromise lengths as iscustomary. Generally, they are cut as half wave dipoles near the low endof the band. This .will vary the reception patterns at other frequenciesbut the general principles of maximum directivity as above set forthwill still be applicable to a satisfactory degree as has been determinedby modern practice.

What is claimed is:

1. A television antenna system comprising a pair of crossed dipoles eachhaving two inner terminal ends and each comprising two dipole rods,wires extending from the four terminal ends, a switch to which saidwires are connected, a manually operated selector member on said switch,a pair of output terminals on said selector member, and means controlledby operation of said selector member for electrically connecting any twoof said dipole rods to said output terminals, and for simultaneouslyshorting the two remaining dipole rods when two adjacent dipole rods areelectrically connected to said output terminals.

2. A television antenna'system comprising four dipole rods extending indifferent directions, each of said dipole rods having an inner: terminalend, a switch having two series of contacts,.each contact of each seriesbeing electrically connected to one of said inner terminal ends, anoutput contact for each series, a selector member for simultaneouslyselecting one contact of each series and connecting it to its outputcontact so as to effectively connect any two of said dipole rods to saidoutput contacts, and means on said switch for simultaneously shortingthe remaining two of said four dipole rods when the other two thereofare connected to said output contacts.

3. A television antenna system comprising .a pair of crossed dipoleseach including two dipole rods so that said pair of dipoles comprisesfour dipole rods, each of the dipole rods having an inner terminal end,a switch comprising a stationary plate having two series of contacts onthe respective sides thereof, each contact of each series beingelectrically connected to one of said inner terminal ends, an outputcontact for each series, a selector member for simultaneously selectingone contact of each series and connecting it to its output contact so asto effectively conne'ct any two of said dipole rods to said outputcontacts, a rotor plate on said selector member, "a pair of selectorrotors on the respective sides of said rotor plate, each of saidselector rotors being adapted to make an electrical connection to one ofthe respective series of contact when said selector member is operated,and a pair of shorting rotors each mounted on the respective sides ofsaid rotor plate,said shorting rotors being interconnected and beingoperative to short the remaining two of said four dipole rods' '4. Atelevision antenna system comprising a pair of crossed dipoles eachincluding two dipole rods so that said pair of dipoles comprises fourdipole rods, each of the dipole rods having an inner terminal end, aswitch comprising a stationary plate having two series of contacts onthe respective sides thereof, each contact of each series beingelectrically connected to one of said inner terminal ends, an outputcontact for each series, a selector member for simultaneously selectingone contact of each series and connecting it to its output contact so asto effectively connect any two of said dipole rods to said outputcontacts, said selector including a rotor plate, a pair of selectorrotors on the respective sides of said rotor plate, each of saidselector rotors having three contacts for efiecting electrical connection with contacts of the respective series when said selector memberisoperated, and a shorting rotorfor shorting the remaining two of said dipole rods mounted on each side of said rotor plate, said shorting rotorsbeing insulated from said selector rotors.

5. For use with a television antenna system having a pair of crosseddipoles each consisting "of two dipole rods "50 that said pair ofdipoles comprises four dipole rods, "a switch for selecting combinationsof said dipole rods for connection to a television receiver, said switchcomprising a stationary plate having two series of contacts on therespective sides thereof, an output contact for 'each' series, "a rotorplate, a 'pair of selector rotors on the respective sides of said rotorplate, each of said rotors being adapted to make an electricalconnection to at least one of the respective series of contacts whensaid selector "member is operated, apairo'f shorting rotors each mountedon the respective sides of said rotor plate and being operative to shorttogether two contacts on the respective sides of said rotor plate whichare not electrically-connected to said selector rotors when saidselector member is operated to make the said electrical connections ofsaid selector rotors, said shorting rotors being interconnected andbeing insulated from said selector rotors. v r v 6. For use with atelevision antenna system having a pair of crossed dipoles eachconsisting of two dipole rods so that'said pair of dipoles comprisesfour dipole rods, ,each o f which has an inner terminal end, a switchfor selecting combinations of said dipole rods for connection to atelevision receiver, said switch comprising a stationary plate havingtwo series of contacts on the re'spective sides thereof, each contact ofeach series being electrically connected to one of said inner terminalends, each series comprising six contacts, one series of contacts havingtwo different contacts thereof connected to each of three of saidterminal ends, and the other series having three of its contactsrespectively connected to the said three terminal ends and the remainingthree contacts connected to the remaining terminal end, an outputcontact for each series, a selector member for simultaneously selectingone contact of each series and connecting it to its output contact so asto effectively connect any two of said dipole rods to said outputcontacts, said selector including a rotor plate, and a pair of selectorrotors on the respective sides of said rotor plate.

' 7. A switch according to claim 6 and wherein each of said selectorrotors has three integral contacts for effecting electrical connectionwith contacts of the respective series when said selector member isoperated.

8. A television antenna system comprising a pair of crossed dipoles eachincluding two dipole rods so that said pair of dipoles comprises fourdipole rods, each of the dipole rods having an inner terminal end, "aswitch comprising a stationary plate having two series of contacts onthe respective sides thereof, each contact of each series beingelectrically connected to one of said inner terminal ends, each seriescomprising six contacts, one series of contacts having two differentcontacts thereof connected to each of three of said terminal ends, andthe other series having three of its contactsrespectively connected tothe said three terminal ends and the remaining three contacts connectedto the remaining terminal end, an output contact for each series, and aselector member for simultaneously selecting one contact of each seriesand connecting it to its output contact so as to efiectively connect anytwo of said dipole rods to said output contacts, said selector includinga rotor plate, a pair of selector rotors on the respective sides of saidrotor plate, each of said selector rotors having three integral contactsfor effecting electrical connection with contacts of the respectiveseries when said selector member is operated.

MARVIN P. MIDDLEMARK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,424,365 Loftin et al Aug. 1,1922 2,186,949 Allison et a1 Jan. 16, 1940 2,368,286 Carlson Jan. 30,1945 2,427,940 Ayres Sept. 23, 1947 2,435,978 Newkirk Feb. 1'7, 19482,552,816 Root May 15, 1951 2,563,243 Hills Aug. 7, 1951

